Pump



Oct. 27, 1959 v c. o. WEISENBACH 0,

I PUMP I Filed Dec. 25, 1954 I 3 Sheets-Sheet l IN VEN TOR.

M m we Oct. 27, 1959 C. O. WEISENBACH PUMP 3 Sheets-Sheet 2 Filed Dec.23, 1954 0 INVENTOR. (944K155 .Wf/ ffi a M/r 959 c. o. WEISENBACH2,910,008

PUMP

Filed Dec. 23, 1954 3 Sheets-Sheet 5 CI... V

' IN VEN TOR. 7 0mm; 4 wm'mmr/l 2 1477??5) United States Patent PUMP ,Application December 23, 1954, Serial No. 477,288

' V 1 Claim. (Cl. 103- 162) This invention relates generally to fluidpumps of the piston type and more particularly to an improvedcombination of such pumps embodying servo control means for adjustingthe stroke'of a portion of said pistons.

It is an object of this invention to provide a unitary pumping deviceembodying two opposed piston pumps having a stroke adjusting controlincorporated therein, and capable of a wide range of operation fromsubstantially no flow to the discharge of large quantities of fluid athigh pressure.

Another object of the invention is to provide a reversible Wobbler-typemechanism with a servo control means for adjusting the stroke of thepistons of one pump and the Wobbler therefor on'both sides of neutral aswell as to its neutral or no stroke position.

Another object of the invention is to provide a variable delivery,unitary pumping deviceembodying two pumps having control meansincorporated therein for operating one of said pumps as a motor during aportion of the operating range of said device.

Another object of the invention is to provide a high capacity, variabledelivery pumping device that is of extremely small size, light weightand having high sensitivity of control.

Other objects and advantages of the invention will become readilyapparent from the following description taken in connection with theaccompanying drawings, in

which:

Figure 1 is atop view of my-invention;

Figure 2 is a longitudinal section taken along line 2--2 of Figure 1;-Figure 3 is a cross sectional View of Figure 1;

Figure 4 is a cross sectional view taken along line 4--4 of Figure 1;and

Figure 5 is a schematic view showing inlet and outlet connections of thepumping unit.

With reference to the accompanying drawings, numeral designates a pumphousing or hollow body closed at either end by plates 12 and 14, thelatter of which may form a portion of the housing 16 of a centrifugalpump 18 which is provided with an end plate 20. An inlet 22 and anoutlet 24 are provided in a wall 26 which separates the interior of thehousing into two chambers 28 and 30. Located in said chambers 28 and 30are plunger housings or rotors 32 and 34, respectively, mounted inopposed relation on a common drive shaft 36 which is journalled in endplates 12 and 14 and at one a pumping device embodying taken "along line3'-3 end is provided with a drive spline 38 which is adapted forconnection with an engine (not shown).

Rotor 32 is constructed and arranged in operative position with one endparallel and in close proximity to a'port insert member 40 which issecured to the wall 26 by suitable pins 42. Port insert member 40 isprovided with kidney shaped ports 44 and 46, best shown in Figure 5,which are in communication with inlet 22 and outlet 24 respectivelythrough conduits 48 and 50.

2,910,008 Patented Oct. 27, 1959 Rotor 32 is formed with a plurality ofcylinders 52 which are disposed at an angle to the axis of rotation ofsaid rotor. As rotor 32 is rotated about its axis, cylinders 52 arearranged to successively register with ports 44 and 46. Sleeves 54 arelocated in the side wall of each of the cylinders 52 to provide abearing surface for plungers 56 which are reciprocably disposed in saidcylinders. Plungers 56 are urged inwardly, in a pumping or fueldisplacing direction, by a wobble plate 58 which is fixed againstrotation but which may be angularly varied about shaft 36 by suitablemeans to be described later. Plungers 56 may be moved outwardly in afuel connection between rotor 32 and shaft 36 so that in event ofcasualty to said rotor the connection mayshear to permit the freerotation of shaft 36 and the continued operation of the remainder of theunit.

Rotor 34 is similar in construction to rotor 32 and is arranged inoperative position in chamber 30 with one end parallel and in closeproximity to a port insert member '70 which is secured to wall 26 bysuitable pin 71. Port insert member is provided with kidney shaped ports72 and 74 which are connected to the inlet 22 and outlet 24 throughconduits 7 6 and 78 respectively. Rotor 34 is formed with a series ofelongated bores or cylinders 80 which are adapted to sucecssivelyregister with ports '72 and 74 as the rotor is rotated about its axis.In each of said cylinders 80 there is mounted a plunger or piston 82positively urged in a fuel-displacing or pumping stroke direction bymeans of a non-rotating, fixed angle cam or wobble plate 84. Piston 82may be returned during the intake stroke by centrifugal force, or bysprings 86, each acting alone or in combination. A plunger return ring88 secured to wobble plate 84 may be provided to assist in the return ofplungers 82. Rotor 34 is driven by shaft 36 through a shear sectionedspline 90 to provide for free rotation of the shaft and continuedrotation of the remainder of the unit in event of a casualty to saidrotor.

Wobble plate 58 is mounted in the housing 10 on a trunnion 92 forrotation on either side of the neutral or no stroke position in responseto regulation by a. servo mechanism designated generally at 100. Withwobble plate 58 in the maximum pumping stroke position, at shown inFigure 2, the discharge from rotor 32 is maximum and is combined withthe discharge from rotor 34 to give maximum flow from the variabledelivery pumping unit. As the wobble plate or cam 58 is rotatedclockwise from the maximum pumping stroke position to the neutral or nostroke position, the flow from the variable delivery unit is reduced toone half the maximum flow. Further rotation of the wobble plate 58 pastthe neutral position causes rotor 32 to be operated as a motor absorbingthe discharge from rotor 34. With the wobble plate in the limitclockwise position, rotor 32 absorbs all or nearly all of the dischargefrom rotor 34 resulting in a substantially zero flow from the variabledelivery pumping unit. In actual practice, however, it is usuallydesirable to maintain a minimum flow through the unit for coolingpurposes. Tests have shown that rotor 32 can absorb about 96 percent ofthe output of rotor 34 without serious temperature rise.

A stop or limit member 102 is threadably secured in the housing 10 andis adapted to butt against wobble wobbleplate 58 to thereby insure aminimum flow I through the unit for cooling purposes.

The servo mechanism 100 consists of a piston 104 adapted to reciprocatein a cylinder 106 and has secured thereto a hollow rod 108 whichprojects through asuitable guide bore 110 formed in housing and connectsby means of a link 112 with Wobble plate 58. Cylinder 106 is dividedinto two chambers114 and 116 by'piston 104. Chamber 114is'incommunication with outlet 24' through passage 118. A bleed passage120 formed inpiston 104 connects chambers 1 14 and 116. Chamber 116 isadapted to be connected to a suitable control means (not shown) by aconduit 122; A bleed passage 1-24 in piston 104 connects chamber 116through conduit 126 and port 128 with chamber'28 which contains fuel atinlet pressure. A spring 130 is located in chamber 116 to urge piston104 in a direction to produce maximum pumping stroke of plungers 56 inrotor 32.

The inlet 132 of centrifugal pump 18'may be connected to a source offluid (not shown) to discharge fluid from outlet 134 through conduit 136(dot-dash line) 'to th inlet 22 of the variable delivery pumping unit.

In the operation of my variable delivery pump unit, fluid is deliveredfrom a source not shown to inlet 132 of centrifugal pump 18 where it isplaced under pressure and discharged from outlet 134 through conduit 136to inlet 22 of the variable delivery pumping unit. With both wobbleplates 58 and 84 in the pumping position as shown in Figure 2, fluidpasses from the inlet 22 through passages 48 and 76 to the kidney shapedports 44 and 72 which are in registration with one or more cylinders 52and 80 of rotors 32 and 34 respectively. Rotation of the common driveshaft 36 brings cylinders 52 and 80 into registration with ports 46 and74 at which time wobble plates 58 and 84 force the plungers 56 and 82inwardly to discharge fuel into conduits 50 and 78 to be expelledthrough a common outlet 24. The inlet ports 44 and 72 are located in theplane passing through diametrically opposed cylinders 52 and 80 formedrespectively in rotors 32 and 34. Outlet ports 46 and 74 are located ina plane passing through diametrically opposed cylinders 52 and 80 inrotors 32 and 34 respectively. The planes passing through the inlet andoutlet ports intersect at a mid-point between two rotors.

Discharge pressure is conveyed to chamber 114 of the servo unit 106through passage 118 to urge piston 104 to the right toward neutral ormotor stroke position. Spring 130 in chamber 116 opposes the pressure inchamber 114 and urges piston 104 to the left toward maximum pumpingstroke position. The pressure in chamber 114 is controlled by regulatingthe bleed through 120 by suit- 4 able means (not shown) connected toconduit 122 whereby piston 104 may be moved to any desired positionbetween maximum pumping and maximum motor stroke position.

It is to be noted that rod 108 is connected to wobble plate 58 on theinlet side of the rotor 32 and is arranged so that the force ofdischarge pressure acting on the plungers 56 forms a couple with theforce acting on servo piston 104 to provide substantially instantaneousreaction of the wobble plate in response to changes of the controlmeans.

While only one embodiment of the invention has been shown and describedin detail it will be understood that this is illustrative only and isnot to be taken as a definition of the scope of the invention, referencebeing bad for this purpose to the appended claim.

I claim:

A fluid pressure apparatus comprising a housing a shaft in said housing;a pair of rotors mounted in opposed relation on said shaft; a pluralityof cylinders in each of said rotors angularly disposed to said shaft,the cylinders in one of said rotors'being diametrically opposed tocorresponding cylinders in the other of said rotors; a plunger in eachof said cylinder; an inlet for each of said rotors, said inlets beinglocated in theplane passing through diametrically opposed cylinders;means connecting said inlets; an outlet for each of said rotors, saidoutlets being located in a plane passing through diametrically opposedcylinders; means connecting said outlets; a fixed wobble plate in saidhousing adapted to engage the plungers in' one of said rotors; a movablewobble plate mounted in said housing for rotation on either side of aneutral position, said movable wobble plate being adapted for engagementwith the plungers in the other of said rotors; and a servo mechanismresponsive to outlet pressure and operatively connected to said movablewobble plate for controlling the position thereof.

Great Britain Oct. 29, 1952 A 4A1:- k.

